Swine Gestation Calculator

What this calculator does

The Swine Gestation Calculator estimates how many days remain until a sow is due to farrow (give birth), based on days since breeding.

The method it uses

Pig gestation is famously remembered by the farmer’s rule of thumb ‘3 months, 3 weeks, and 3 days,’ which works out to 114 days on average. This calculator subtracts the days already elapsed from that 114-day standard to estimate days remaining, and also reports weeks pregnant and percent of pregnancy complete.

Individual sows commonly farrow within a couple of days of this estimate. This tool is for general herd-management planning; consult a veterinarian for confirmed pregnancy staging.